为得到高精度的轧机机电液系统整体动态模型,将先进的控制理论应用于传统的轧制领域和提高板带产品质量精度,建立四辊轧机厚度控制系统动态模型,包括轧制过程模型、机架-辊系动态模型和液压伺服系统模型,将三个模型耦合并线性化,得到四辊轧机厚控系统多输入多输出(Multiple input multiple output,MIMO)线性化传递函数模型。考虑最终板厚质量指标,简化MIMO系统,得到基于测厚仪监控的板厚控制系统模型。利用H∞混合灵敏度鲁棒控制理论,采用遗传算法优化选取加权函数,设计H∞鲁棒控制器。仿真研究结果及与常规比例积分微分(Proportional integral derivative,PID)控制效果的比较表明,所设计的控制器对于厚度控制系统的外界扰动和参数不确定性具有较好的抑制性能,提高了测厚仪监控厚度控制系统的动态性能和稳定性。
In order to build high accuracy integral dynamic models of rolling mill system, apply advanced control theory in the traditional rolling field and improve the quality and precision of strip, dynamic model of gauge control system of 4-h mill is built, including the rolling process model, the mill stand-rolls dynamic model and the hydraulic servo system model. The three models are coupled and linearized, then the multiple input multiple output (MIMO) linear transfer function model of 4-h mill system is obtained. Simplify the MIMO linear model, considering the quality of the product, the plate thickness control system based on thickness gauge monitoring is obtained. The H∞ robust controller is designed by using the H∞ mixed sensitivity robust control theory. The weight functions are selected based on genetic algorithm. Simulation results and comparison with the effect, of proportional integral derivative (PID) control show that the H∞ robust controller designed has better disturbance attenuation performance for parameter uncertainty and external disturbance. The dynamic performances and stability of the thickness control system are improved significantly.